Project Summary The United States has a large and rapidly growing Latino population. At the same time, Latinos and transgender persons in the US carry disproportionate HIV burden. Currently, no efficacious HIV prevention interventions exist for transgender persons who have sex with men. In response to RFA-PS-16-003 ?Evaluating Locally-Developed or Adapted (Homegrown) Combination HIV Prevention Interventions for Transgender Persons who have Sex with Men?, our community-university partnership proposes a 4-year study (U01) to refine, fully implement, and rigorously evaluate a small-group combination intervention designed to promote behavioral, biomedical, and social/structural approaches to HIV prevention by increasing condom use, HIV testing, PrEP use, and use of safe transition-related healthcare services among Latina transgender women who have sex with men. The intervention, known as Chicas Creando Acceso a la Salud (ChiCAS; Girls Creating Access to Health), was developed locally by a community-based organization, in partnership with Latina transgender women, and is informed by social cognitive theory and theory of empowerment education. Although data suggest that ChiCAS is promising, it has not yet been evaluated. The proposed study is a result of a well-established community-university partnership. A total of 100 Latina transgender women who have sex with men will be enrolled. Participants will complete an initial baseline assessment designed to measure current sexual health behaviors, healthcare use, and psychological, social, and cultural influences on sexual behaviors and healthcare use. Participants then will be randomized to the 4- session small-group combination HIV prevention intervention group or a delayed-intervention comparison group (waitlist). All participants also will complete identical assessments at 3-month and 6-month follow-up. Participants in the HIV prevention intervention, relative to their peers in the delayed-intervention comparison group, are anticipated to demonstrate (a) increased self-reported use of condoms during sexual intercourse; (b) increased HIV testing; (c) increased use of PrEP; and (d) increased use of safe transition-related healthcare services (including medical care and mental health services). The results and products from this study will be disseminated to inform public health practice, research, and policy. Results and products will include: (1) a Spanish-language combination small-group HIV prevention intervention that is: culturally congruent, designed to reduce risk among Latina transgender women, and ready for dissemination and further implementation if found to be efficacious; and (2) a deeper understanding of HIV risk, use of transition-related healthcare services, and intervention among Latina transgender women.